Method of preparing enzyme stable starch and product



United States Patent 3,332,786 METHOD OF PREPARING ENZYME STABLE STARCHAND PRODUCT Ray L. Edliu, San Diego, Calif., assignor to Kelco Company,San Diego, Calif., a corporation of Delaware No Drawing. Filed June 13,1966, Ser. No. 556,903

, 14 Claims. (Cl. 99139) This invention relates to the stabilization ofstarch against enzymatic degradation. More particularly, the inventionrelates to the stabilization of starch by the addition thereto ofpropylene glycol alginate.

The enzymatic degradation of starch, particularly by amylase enzymes,has long been a problem. Previous attempts to stabilize starchagainstenzymatic degradation have not been successful. I

Starch is commonly employed-in thickening various foods. To cite but afew, starch is commonly employed as a thickener in the preparation ofbaby foods and summer fillings such as a custard type pie filling or acustard type dessert. Frequently, in the consumption of s'uch'a food, itwill come in contact with a sourceof an amylase enzyme. To illustrate,in feeding a baby from a container of baby food, the spoon used infeeding the baby will frequently be dipped into the food container.Amylase enzymes are commonly present in saliva and thus are transferredto the contents of the container on the spoon. The effect of amylaseenzymes on starch is a dramatic one. In the case of baby food, thetransfer of amylase enzymes to the food can reduce its thickness toslightly more than that of water'in thirty minutes or less. The body ofthe baby food is then essentially destroyed and it isno longer desirablefor consumption. j

An object of my invention is toprovide a method for stabilizing starchwhich greatly improves its stability to degradation by amylase enzymes.

A further object of my invention is to provide a method of stabilizingstarch against degradation by amylase enzymes by the addition to thestarchof propylene glycol alginate.

Additional objects will become apparent from a reading of thespecification and claims which follow.

In the practice of my invention, I have found that the presence ofpropylene glycol alginate in admixture with starch stabilizes the starchagainst. degradation by amylase. enzymes in an aqueous acid environment.The quantity of starch present can, for example, range from about 0.5 toabout 8.0% by weight and the quantity of propylene glycol alginatepresent can range from about 0.1 to about 2.0% by weight. H

I have found that the presence of propylene glycol alginate with starch,particularly in the relative proportions specified above, reducesdegradation -of the starchby amylase enzymes within the pH range fromabout 3.0 to about 4.5. However, I have found that my'method of sta-.bilizing starch works best within the pH range from 3 to 4.

Propylene glycol alginate is described in US. Patent 2,426,125entitled-Manufacture of Glycol Alginates. It has been available as aproduct of commerce for some time and is obtainable in a variety offorms, all of which are suitable in practicing the method of the presentinvention.

In addition to the propylene glycol alginate and starch in the aqueousmedium, other ingredients may also be "ice present. To illustrate, theaqueous medium can contain sistance to degradation by amylase enzymes.

I have found that all starches may be stabilized accord ing to themethod of my invention. To illustrate but a few, I have found thatnatural or modified starches derived from corn, wheat, potatoes, Waxymaize and tapioca are all improved. In addition, pregelatinized starchesare also improved by my invention.

To further illustrate my invention, there are presented the followingexamples in which all parts and percentages are by weight unlessotherwise illustrated.

Example I Samples were prepared by dry mixing a modified waxy maizestarch with a propylene glycol alginate and adding the mixture to waterwith good agitation. The water employed in preparing the samples was a5050 volume blend of tap water and distilled Water. After stirring untilthe sample was substantially homogenous, it was cooled in a tap waterbath and stirred still further to insure homogeneity. The sample wasthen heated to C. and held at this temperature for about 20 minutes toinsure gelatinization of the starch. Following this, the sample wascooled to 24 C. using a tap water bath. The initial vis cosity of thesample was then recorded with a model LVF Brookfield Viscometer. Thesamples were then inoculated with 1 milliliter of a diastase solutioncontaining 0.007 gram of amylase in 1 milliliter of distilled water. Thediastase solution was mixed into the samples by using a spatula. Theviscosity was then measured at various time intervals of 2, 4, 8, l6 and32 minutes after inoculation with the enzyme. Following'a 24-hourperiod, the viscosity of the sample was again measured using aBrookfield Viscometer. g

The results of these tests are set forth in the following Table I. Theweight percent of modified waxy maize starcl (ClearjelNational'Starch &Chemical Corp.) is set fortl in Table I and the quantity of propyleneglycol alginatt is set forth in Table II. Also set forth in Table II isdesignation of the particular propylene glycol alginat as Kelcoloidfollowed by a number. The number indicate;

a particular grade of propylene glycol alginate sold by th Kelco Companyof San Diego, Calif., under the trade mark Kelcoloid. The total quantityof each sample wa grams and thus the weight percent of starch antpropylene glycol alginate set forth in columns I and 2 in dicate theweight of each material in grams in the 10 gram sample. The initialviscosity of the sample (prior t1 inoculation with the diastasesolution) is set forth in th next column followed by the viscosities ofthe samples a various time intervals after inoculation in the succeedin.

columns. The pH of the samples is set forth in the las column.

TABLE I Brookfield viscosity, cps. Starch, Propylene glycol alginate, pHof Sample weight weight percent (Minutes) (Hours) sample percent 3. 750.3 Kelcoloid KDHVF 831 775 774 777 807 850 1, 973 4. 26 3. 0.3Kelcoloid KDHVF 712 610 604 604 664 750 1, 180 4. 13 2.8 0.6 KelcoloidKDHVF 478 407 388 415 417 421 1, 095 3. 97 2. 2 0.8 335 287 289 295 305328 804 3. 76 1. 6 1.0 326 250 261 265 280 305 640 3. 71 1. 2 1.2 343251 252 262 268 296 640 3. 64 1. 0 1.3 442 362 368 378 393 426 851 3. 633. 75 0.3 446 340 343 344 335 349 390 4. 12 2. 8 0.6 237 193 195 192 181163 232 4. 0 2. 2 0.8 96 97 97 100 88 102 180 3. 77 1 1. 6 1.0 KelcoloidKDLVF 109 107 108 111 106 113 178 3- 75 2 1. 2 1.2 Kelcoloid KDLVF 81 9798 101 124 130 288 3. 70 3 1. 0 1.3 Kelcoloid KDLVF 143 136 135 138 137140 297 3. 66 2.8 0.6 Kelcoloid KDL 83 84 84 87 87 84 68 4. 2. 2 0.8Kelcoloid KDL 67 72 72 73 75 75 67 4. 35 1. 6 1.0 Keleoloid KDL. 75 7373 72 71 72 66 4. 33 1. 2 1.2 Kelcoloid KDL 63 68 67 68 68 65 67 4.29 1. 0 1.3 Kelcoloid KDL 60 62 54 53 4. 25 2. 8 0.6 Kelcoloid KDO. 7371 64 51 65 48 4. 05 2. 2 0.8 Keleoloid KDO 51 50 52 51 51 48 55 4.00 1. 6 1.0 Kelcoloid KDO 45 47 48 48 47 50 56 3. 1. 2 1.2 Kelcoloid KDO47 53 53 53 53 54 56 3.13 1. 0 1.3 Keleoloid KDO 51 55 55 55 54 55 55 4.16

As shown 1n the foregoing table, all of the various Example II rades ofpropylene glycol alginate in varying amounts 'ith respect to the starchpresent, were successful in stailizingthe starch against enzymaticdegradation. The litial viscosity of the sample was alfected by thegrade E propylene glycol alginate which was employed. For (ample, theKelcoloid KDHVF grade, which is a high iscosity propylene glycolalginate, gave a higher sample Iscosity than the other grades ofpropylene glycol algiate. However, the change in the viscosity of thevarious .mples with time did not vary appreciably from one gradepropylene glycol alginate to the next. All were effective stabilizingenzymatic degradation of the starch and ereby maintaining the viscosityof the sample. The increase in viscosity noted in some of the examplesnot entirely understood. It is believed that it may be due some crosslinking of the algin molecules and/or re- :tion of the algin with starchin some as yet unknown anner. In any event, the increase in viscosity isnot a sult of enzymatic degradation of the starch which prolces just theopposite resulta sharp decrease in the icosity of the sample. In orderto make certain that the observed stabilization 15 not merely the resultof some enzymatic decomposiin of the propylene glycol alginate, severaladditional periments were performed. In these experiments, 1% by :ightaqueous solutions of various grades of propylene zcol alginate wereinoculated with 1 milliliter of a dia- LS6 solution containing 0.007gram of amylase in dis- .ed water. The initial viscosity of thepropylene glycol ;inate solution was determined and the viscosity wasain determined after 24 hours to determine whether are had been anychange due to inoculation with the zyme. One hundred grams of a 1%propylene glycol ;inate (Kelcoloid KDHVF) had an initial viscosity of 00cps. as measured with a Brookfield Viscometer. e pH of the system wascontrolled by the addition of M acetic acid to a pH of 3.52. Afterinoculation with nilliliter of the diastase solution, the viscosity ofthe :tem was again measured after 24 hours and found to 2370 cps. Thetest was repeated using grams of 1% solution of propylene glycolalginate (Kelcoloid )LVF) at a pH of 3.47. The initial viscosity wasfound be 316 cps. and the viscosity 24 hours after inoculan With 1milliliter of the diastase solution was 374 cps. ese tests clearly showthat propylene glycol alginate is affected by amylase enzymes and thatthe effect of propylene glycol alginate in stabilizing the enzymaticgradation of the starch is not due to an enzymaticreion with thepropylene glycol alginate. 5

In a further series of tests, conducted in the same manner as those setforth in Example I and Table 1, samples were made up which contained amodified waxy maize starch in combination with varying amounts ofpropylene glycol. The initial viscosity of the sample was determinedusing a Brookfield Viscometer and 1 milliliter of 3 diastase solutioncontaining 0.007 gram of amylase in distilled water was then used toinoculate the samples. Following inoculation, the Brookfield viscosityof the samples were determined at 2, 4, 8, 16 and 32 minutes and laterat 24 hours. The pH of the various samples was controlled by theaddition thereto of 0.1 M acetic acid.

The results of the tests are shown in the following Table II. In eachtest, a 100 gram sample was used. The weight percent of modified waxymaize starch (Clearjel) is set forth in column 2 and the weight percentof propylene glycol is set forth in column 3. The Brookfield viscosityat various time intervals is set forth in the succeeding columns and inthe last column is set forth the pH of the sample.

TABLE II (Part 1) Sample Starch, weight percent Propylene glycol,

weight percent (Part 2) Brookfield viscosity, cps.

I pH of Sample (Minutes) (Hours) sample As shown in the above table, thepresence of propylene glycol per so had no discernible efiect instabilizing the starch against enzymatic degradation. Although theviscosity of the individual samples varied somewhat initially, all haddegraded to the low viscosity of 7 cps. after a time period of 24 hoursfollowing inoculation with the amylase enzyme.

Example III A number of tests were performed to determine the effect ofpH on the enzymatic degradation of starch. In these tests, a samplecontaining 95 grams of water and 6 parison of the results in Table IVwith those of Table I shows that there is no appreciable ditference inresult between adding the propylene glycol alg-inate prior to cooking oradding it subsequent to cooking of the starch. In either case, thepropylene glycol alginate stabilizes 5 grams of a modified waxy maizestarch (Cleanel) was 5 cooked as described previously and the pH wasthen the starch agamst epzymam degradatlon adjusted by the addition ofan acid. The initial Brook- In other tfests whlch were calcmm glucon'field viscosity was determined and the sample was then magneslumPhosphate f PeXametaPhQSPhaFe inoculated with 1 milliliter of an aqueousdistaste 501w and the sodium salt of ethylene diamine tetraacetic ac1dtion containing 0.007 gram of amylase enzyme in dis- 10 (versenate) wereadded to a mixture of a modified y tilled water. The viscosity was thendetermined at premaiZfi Starch in Combination With P PY glycol scribedtime intervals following inoculation. Results of a g te (Ke d HVF) inWhich the Starch had the tests are set forth in the following Table III.been cooked in the manner of Example I. It was found TABLE IIIBrookfield viscosity, cps.

pH of sample Sample, 100 and acid emarms or (Minutes) (Hours) ployed toad-' starch solution just pH 0 l 2 l 4 s 32 24 23 970 1,374 1,123 340 is6 s 4.10

(0.1 N HCl). 1, 213 1, 500 1,120 610 257 10 9 3.50

' (Citric acid). 31 1,100 1, 300 1, 340 1,234 014 107 7 3.35

(Citric acid). 32 774 310 90s 1, 044 1,040 460 10 3.40

(0.1 M acetic acid).

As shown inthe above table, all of the starch samthat the initialviscosity of the sample was increased apples were enzymatically degradedwithin a 24 hour preciably when calcium was added. The addition 01period when the starch samples had a pH within the phosphates was foundto reduce the initial viscosity general range of 3 to 4. Certain samplesdegraded more and the use of magnesium also was found to give a lowe:rapidly than others. The important thing, however, is initial viscosity.None of these mate-rials, however, wal that all were degraded to athickness only slightly above found to interfere with the protectiveaction of propylem that of water in a 24 hour period. glycol alginate instabilizing the starch against enzymatii degradation within the generalpH range of 3 to 4. Example IV 40 Example V V -In a still further seriesof tests, the starch was pre- A still further series of tests wasperformed to deter pared by cooking in a water bath at a temperature ofmine the effectiveness of propylene glycol alginate i1 about 190 F. for30 minutes. Following this, the stabilizing various starches. In each ofthese tests, th propylgene glycol alginate was added and the sample 5propylene glycol alginate and starch were mixed drj was cooled to atemperature of about 24 C. and its visand added to water with stirring,after which the mix cosity was determined with a Brookfield Viscometer,ture was heated to 95 C. as in Example I, held at thi Model LVF. Each ofthe 100 gram samples was then temperature for 20 minutes, cooled to 24C., and th inoculated with 1 milliliter of a disastase solution c0n-Brookfield viscosity determined in centipoises. Th taining 0.007 gram ofamylase enzyme in distilled W te samples were then inoculated witheither 1 milliliter o The viscosity of the various samples were thendeterdisastase solution (0.007 gram of amylase per millilite mined 24hours after the addition of the amylase of distilled water) or with lmilliliter of saliva. Th enzyme. The pH of all of the test samplesvaried be- Brookfield viscosities were then determined at variou tweenabout 3.4 and about 3:6. The results of these time intervals afterinoculation. The results are set fort te s a e t forth i the followingTable IV. in the following Table v. Each of the samples weighe 100grams, and the pH was controlled by the additio TABLE Iv of 0.1 M aceticacid. V. 1 The data presented in Table V clearly demonstratior SampleStarch, Propylene glycol alglnate, 15005 that propylene glycol alginateis effective in stabilizing Weight weight percent variety of starches.The modified tapioca starch whlc percent 24 hours was tested is soldunder the trade name Purity D; the prr 1 gelatinized modified waxy maizestarch is sold under th 2; Z 32%333313 g$ 2: ,1383 trade name InstantClearjel; and the modified wheat starc 9 61760 71670 is sold under thetrade name Paygel. As might be e: Kelmlold KDHVFM 5'660 7540 pected, thepregelatinized starch gave much higher san ple viscosities than theother starches. However, the m The results of Table IV show thatpropylene glycol change of the sample viscosities after inoculationshowe alginate is effective in stabilizing starch according to that allof the starches were stabilized against enzymat the method of theinvention when the alginate is added degradation by the presence of thepropylene glyc to the starch after it has been suitably cooked. Acomalignate.

TABLE V (Part 1) Starch, weight percent Propylene glycol alginate,

weight percent Enzyme Raw Corn Starch 1 Keleoloid KDHVF ..do do 5Modified Tapioca Starch do do .do

5 Pregelatinlzed Modified Waxy do Mdaize Starch.

o 5 Mgdlfied Wheat Starch Amylase. Saliva.

(Part 2) Brookfield viscosity, cps.

pH of Sample (Minutes) (Hours) sample Example VI 30 alginate. It wasfound that the baby food containing 100 gram sample was prepared by theaddition of 6 rams of a modified waxy maize starch (Clearjel) and gramof propylene glycol alginate (Kelcoloid KDHVF) 1 93 grams of water. Theingredients were first mixed ry and then added to the water withstirring, after which 1e mixture was heated to about 95 0., held at thistemerature for about 20 minutes and then cooled to about 4 C. Thissample was stored at this temperature for 24 ours and its viscosity wasthen determined with a Brookeld Viscometer and found to be 86,500 cps.The sample as then inoculated with 1 milliliter of a diastate solution)ntaining 0.007 gram of amylase in distilled water. The scosity of thesample was determined 24 hours after roculation and found to be 98,000cps. The pH of the tmple was 3.53.

The results of Example VI show that the stabilization 3 starch by thepresence therewith of propylene glycol ginate does not changeappreciably with the passage F time. Thus, even after being stored for24 hours prior inoculation with enzymes, the starch was suita'blya'bilized against enzymatic deterioration.

Example VII The procedure employed in Example VI was repeated :ing a 100gram sample prepared by the addition of 6 'ams of a modified waxy maizestarch (Clearjel) and gram of propylene glycol alginate (KelcoloidKDLVF) 93 grams of water. The pH of the sample was 3.55. fter storagefor 24 hours at about 24 C., the Brookfield scosity of the sample Was42,000 cps. The Brookfield scosity 24 hours after inoculation with 1milliliter of a astase solution containing 0.007 gram of amylase instilled water was 42,600- cps.

The results of Example VII further confirm Example in showing thatstabilization of starch by the addition ereto of propylene glycolalginate is not affected apeciably by the passage of time. The lowersample vissity observed in Example VII resulted from the use of lowerviscosity grade of propylene glycol alginate. Both Examples VI and VII,however, there was no loss in scosity after inoculation with thediastase solution.

To demonstrate the utility of my invention in stabilizg a food productagainst enzymatic degradation, starchntaining orange pudding baby foodswere prepared 'th with and without the addition of propylene glycolpropylene glycol alginate in combination with starch was protectedagainst enzymatic degradation whereas the control product whichcontained no propylene glycol alginate was enzymatically degraded. Theresults of these tests are shown in the following example.

Example VIII An orange pudding baby food was prepared by dry blending 6parts of a modified waxy maize starch (Clearjel), 3 parts of sugar, 0.5part of salt, and 2.0 parts of non-fat dry milk solids, which were thenadded with agitation to 83.5 parts of water and 4 parts of orange juice.The mixture was then heated to 180 F. and held at this temperature for15 minutes. It was then heated to 220 F. and allowed to cool and set for24 hours. The pH of the orange pudding was 3.8, the total weight ofpudding was grams, and the Brookfield viscosity after setting for 24hours was 3000 cps. The sample was then inoculated with 0.5 milliliterof salvia and allowed to set for an additional 24 hours. At this pointthe Brookfield viscosity was measured and found to be 21 cps.

A further orange pudding baby food was prepared by dry blending 0.4 partof propylene glycol alginate (Kelcoloid KDHVF), 3 parts of sugar, and 4parts of a modified waxy maize starch (Clearjel). The ingredients werethen added to 4 parts of orange juice in admixture with a much largerquantity of water. The mixture was then heated to F. at which point anaqueous slurry containing 2 parts of non-fat milk solids, 0.5 part ofsalt, and 0.08 part of dicalcium phosphate diyhdrate were added. Thetotal quantity of water contained in the mixture including that addedwith the slurry was 86.1 parts. The mixture was then heated for 15minutes at 180 F. and heated further to 220 F. after which it wasallowed to cool and set for 24 hours. The pH of the resulting orangepudding was 3.9, the total weight of pudding was 100 grams, and theviscosity after setting for 24 hours was 3100 cps. The sample was theninoculated with 0.5 milliliter of saliva and allowed to set for anadditional 24 hours at which point the viscosity was again measured andfound to be 3210 cps.

The results set forth in Example VIII demonstrate the effectiveness ofpropylene glycol alginate in stabilizing the starch present in theorange pudding baby food against enzymatic degradation. In the samplewhich contained no propylene glycol alginate, enzymatic degradation wasclearly evidenced by the great reduction in the viscosity 24 hours afterinoculation with saliva. In contrast, the sample containing propyleneglycol alginate showed no evidence of enzymatic degradation after a 24hour period.

As shown by the foregoing examples, my invention provides an efiectivemeans for stabilizing a wide variety of starches against enzymaticdegradation within the general pH range from about 3.0 to 4.5.Stabilization of the starch by the propylene glycol algin-ate is notaffected by the addition of other ingredients as commonly found invarious food products and any of the various grades of propylene glycolalginate may be employed.

In the foregoing examples, various references have been made to specificconcentrations of ingredients, temperatures, heating times, and thelike. It should be understood that these references are solely forpurposes of illustration and are not intended to limit the scope of myinvention. I desired that my invention be limited only by the lawfulscope of the appended claims.

I claim:

1. A method of stabilizing a gelatinized starch to enzymatic degradationin an aqueous acid environment within the pH range from about 3 to about4.5, the starch content of said aqueous environment ranging from about0.5 to about 8% by weight, said method comprising adding to saidenvironment from about 0.1 to about 2% by weight of propylene glycolalginate.

2. The method of claim 1 wherein the pH range is from about 3 to about4.

3. The method of claim 1 wherein said starch is stabilized todegradation by amylase enzymes.

4. The method of claim 2 wherein said starch is a modified waxy maizestarch.

5. The method of claim 2 wherein said starch is a modified tapiocastarch.

6. The method of claim 2 wherein said starch is pregelatinized.

7. The method of claim 2 wherein said starch is a modified wheat starch.

8. A starch-containing food product having a pH from about 3.0 to about4.5, said product containing Water, from about 0.5 to about 8% of agelatinized starch susceptible to enzymatic degradation, and from about0.2

to about 2% by weight of propylene glycol alginate, said propyleneglycol alginate being effective to stabilize said starch againstenzymatic degradation.

9. The starch-containing food product of claim 8 wherein said foodproduct has a pH in the range from about 3.0 to about 4.0.

10. The starch-containing food product of claim 9 wherein said starch isa modified waxy maize starch.

11. The starch-containing food product of claim 9 wherein said starch isa modified tapioca starch.

12. The starch-containing food product of claim 9 wherein said starch ispregelatinized.

13. The starch-containing food product of claim 9 wherein said starch isa modified wheat starch.

14. A method of stabilizing a gelatinized starch to enzymaticdegradation in an aqueous acid environment within the pH range fromabout 3 to about 4.5, the starch content of said aqueous environmentranging from about 0.5 to about 8% by weight, said method comprisingadding propylene glycol alginate to said environment in an effectiveamount to stabilize said gelatinized starch against enzymaticdegradation.

Kelco Algin, copyright Oct. 5, 1961, Kelco C0,, Los Angeles, pp. 2, 5, 6and 7.

A. LOUIS MONACELL, Primary Examiner.

RAYMOND N. JONES, Examiner.

J. M. HUNTER, Assistant Examiner.

1. A METHOD OF STABILIZING A GELATINIZED STARCH TO ENZYMATIC DEGRADATIONIN AN AQUEOUS ACID ENVIRONMENT WITHIN THE PH RANGE FROM ABOUT 3 TO ABOUT4.5, THE STARCH CONTENT OF SAID AQUEOUS ENVIRONMENT RANGING FROM ABOUT0.5 TO ABOUT 8% BY WEIGHT, SAID METHOD COMPRISING ADDING TO SAIDENVIRONMENT FROM ABOUT 0.1 TO ABOUT 2% BY WEIGHT OF PROPYLENE GLYCOLALGINATE.